A core component to any good disaster recovery scenario is backing up your systems. In this lesson, you'll learn how to decide when to perform backups, what to back up, and how to ensure that backups are useful.
After this lesson, you will be able to
Estimated lesson time: 30 minutes
It is assumed that you'll have a backup regime in place prior to the migration. The backup policy might consist of full backups at regular intervals and differ-ential or incremental backups in between. Depending on the arrangement of resources on the network, the user files might be backed up separately from the Windows NT information, or in conjunction with it. For comprehensive information about system recovery, consult Part 3, "System Recovery," of the Microsoft Windows 2000 Server Operations Guide volume of the Microsoft Windows 2000 Server Resource Kit.
Magnetic tape is the primary backup medium in use today. Drive types include digital audio tape (DAT), quarter-inch cartridge (QIC), 8mm cassette, and digital linear tape (DLT). Such devices are almost always connected via a SCSI controller. Please bear the following in mind:
There are two levels of backup verification:
The Windows 2000 Backup program can be used to verify a backup against the original files to help prove the validity of the backup. However, even though this procedure is performed on a live system, there will be files that have been changed since the last backup and some of the verifications will be out of date. Hence, the last backup times should be taken into consideration when examining the backup log.
The only way to prove that a system can be restored from a backup set is to perform an actual restore. To avoid disruption of the production environment, the restore can be performed on a system that is offline, provided that it has an identical hardware configuration (such as a tape backup device) to the original. It's also important that once the restore procedure has been proved, any changes to the underlying system such as the addition of hardware (for example, a new or different disk controller) should be followed by a backup and a verified restore.
If you make changes to the hardware of your systems, you might be unable to restore backups that were taken previously unless the tape drive and tape controller are supported in the configuration.
The Windows 2000 Backup program can be started by opening Run on the Start menu and typing ntbackup. Backup provides three wizards that assist in performing a backup, performing a restore, or building a set of Emergency Repair Disks (ERDs).
Ntbackup can back up to a file instead of to a backup device. It's also possible to schedule the backup from within the program. Previous versions of backup were started by a batch file that had to be scheduled by hand.
There are five backup modes:
In previous versions of Windows NT, the backup program provided the option to back up the registry along with the data files being stored. In Windows 2000, this information is referred to as the system state data, which is made up of the following:
All of these items are saved and restored automatically. An option to back up system-protected files in addition to the system state data is provided in the advanced backup options.
If a backup set containing the system state data is restored to an alternate location (in other words, a drive, computer, or directory different from the source), Active Directory directory services, the Certification Services database, and the Components Services Class registration database aren't restored.
It's possible to back up and restore to and from any of the supported Windows 2000 file systems. As with previous versions of backup, when restoring a backup created from an NTFS drive to drives using FAT 16 or FAT 32, all the file ownership and protection is removed.
If data from a Windows 2000–version NTFS volume is restored to a Windows NT 4.0–version NTFS volume, this can result in the loss of security, quotas, and directory attributes.
Because it's possible to overcome file-system security by backing up and restoring files, it's important to restrict the number of personnel who can perform these tasks. For medium- and high-security installations, the right to back up should be given to some operators and the right to restore to others.
During the migration, a domain might contain Windows 2000 servers and Windows NT BDCs. In this configuration, you can run the Windows NT backup program on the Windows NT servers and the Windows 2000 backup program on the Windows 2000 servers.
You might want to consider third-party backup systems because they have several advantages, such as the ability to back up open files.
Imaging a system involves making a complete copy of the partition information, programs, and data on a volume, either by performing a direct copy to a set of CDs or by transferring the image over a network connection. Because the imaging process drives the disks at a low level, it can be performed quickly.
Although you can use the Windows NT backup program to perform these back-ups, it is strongly recommended that whenever possible disk imaging be used instead. Imaging provides a quick way to restore the situation prior to the upgrade attempt, which will both speed up the recovery process and also allow faster retries if a migration fails.
Imaging can be used to good effect during a migration. It provides a means of taking a snapshot of a system. There are three main benefits of imaging:
The disadvantage to an image is that your users won't be able to access the server while the image is being created. Wherever possible, you should consider imaging as an alternative method for one of the data recovery milestones.
The Windows 2000 Recovery Console is a text-mode command interpreter. It can be used to attempt to recover from damage done to disks or Windows system files without resorting to a complete restore, which would require the use of Emergency Repair Disks. To access the Recovery Console, follow these steps:
You can preinstall the Recovery Console on a working Windows 2000 installation by inserting the Windows 2000 installation CD and typing at a command prompt: D:\i386\winnt32.exe /cmdcons, where D is the letter of the CD-ROM drive. Then the Recovery Console will be available at boot time on the Windows 2000 startup menu. In a rare case where you can't boot from the hard disk at all, you'll need to fall back to the previous steps to access the Recovery Console directly from the installation CD.
Once the correct password has been entered, the Recovery Console will start. You'll see a command prompt and be able to read and copy files and perform other actions.
The commands available in the Recovery Console are powerful. It's possible to change partition information, rebuild disks (using Diskpart), start and stop services (using Enable), and perform a variety of low-level actions. Use it with care to avoid causing further damage to a system.
Although you can use the Recovery Console to read files from floppy disks and CD-ROMs, permission is required to allow users of the Recovery Console to save information to the floppy disk. This permission can be modified by changing the appropriate Recovery Console security option, as shown in Figure 12.2.
Figure 12.2 Setting Recovery Console security
In the preceding section, you pressed the R key when booting from the Windows 2000 installation CD to start the Recovery Console. If you had pressed R on the Repair Options screen instead, you would have been prompted to insert an Emergency Repair Disk. The Emergency Repair Disk allows you to repair the boot sector and check the Windows 2000 system files and startup environment. Remember that the ERD must have been created before you need to use it. To create the Emergency Repair Disk, follow these steps.
The Windows 2000 Backup program will prompt you to insert a floppy disk.
Backup will then create your repair disk, as shown in Figure 12.3.
Figure 12.3 Creating an Emergency Repair Disk
Obviously, a full backup of the entire system should be performed prior to starting the migration. There will be other well-defined points at which the system should be backed up so that a failure at any phase won't require a complete return to the premigration situation. These backup points should be planned as part of the migration process. Depending on the migration, milestones at which full backups should be performed are shown in Table 12.1.
Table 12.1 Data Backup Milestones
|Milestone||Backup Windows NT Source||Backup Windows 2000 Destination|
|Creation of pristine environment||Yes|
|Migration of DNS, DHCP, or WINS services (before and after)||Yes||Yes|
|Upgrade of a PDC in a domain (before and after)||Yes|
|Upgrade of a BDC in a subnet (before and after)||Yes|
|Successful migration of users, groups, and machines (before and after)||Yes||Yes|
|Before decommissioning source domains||Yes|
A proliferation of backup methodologies exists. As storage becomes larger, it is increasingly essential that the restore process doesn't take several days. If your budget allows, in addition to tape technologies, look at storage area networks and subsystems that use hard disks as the backup methodology. Using storage area networks is a method of storing all information on an array of hard disks that are separate from all servers and accessed via the LAN.
In this practice, you'll use the Windows 2000 Backup wizard to back up the user directory on TRAINKIT1.
Windows 2000 Backup will now start, as shown in Figure 12.4.
Figure 12.4 Windows 2000 Backup
Now you'll see the Backup window shown in Figure 12.5. Your screen will differ according to the number of drives in your system.
Figure 12.5 Backup Selection screen
The Backup Job Information dialog box will appear and summarizes the backup options selected. It also allows you to select whether to append the saved information and to schedule backups, as shown in Figure 12.6.
Figure 12.6 Backup Job Information dialog box
Figure 12.7 Advanced Backup Options dialog box
The backup will now start and the Backup Progress dialog box will be displayed, as shown in Figure 12.8.
Figure 12.8 Backup Progress dialog box
Figure 12.9 Backup report
Experiment further with the backup process by using the Restore and Schedule tabs of the Backup program.
In this lesson, you learned the importance of the backup in a migration. You saw the different forms of backup that can be performed and the key features of the Windows 2000 Backup program. You also learned about the value of creating images of volumes, as well as the availability of enhanced third-party backup programs. In addition, you learned the importance of verifying that a backup has been performed correctly and that it can be used to rebuild a system from scratch. Finally, you identified a set of milestones in the migration at which points the systems are to be backed up.